Washington: A new research has identified four genetic variants associated with an increased risk of esophageal cancer and its precursor, a condition called Barrett's esophagus.

The study has been conducted by Thomas L. Vaughan, M.D., M.P.H., a member of the Epidemiology Program in the Public Health Sciences Division at Fred Hutch, and David Whiteman, Ph.D., head of the Cancer Control Group at QIMR (formerly known as the Queensland Institute for Medical Research).

To better understand the role of genetics in Barrett's and esophageal cancer, Vaughan and his colleagues pooled data and DNA specimens from 15 international studies conducted in the past 20 years to estimate the heritability of these conditions and identify genetic variants associated with increased risk.

Altogether they gathered DNA samples and lifestyle risk-exposure data from more than 8,000 study participants, including about 5,500 with esophageal cancer or Barrett's esophagus and about 3,200 participants without these conditions who served as a comparison group.

To increase the statistical power of the study and its ability to identify potential causal genetic mutations, information on control subjects gleaned from public data repositories was added to the mix.

After combing through all of the data, the researchers identified genetic variants at three locations - on chromosomes 3, 9 and 19 - as being significantly associated with esophageal adenocarcinoma and Barrett's esophagus. In addition, they found that a genetic variant on chromosome 16 that had been previously linked to Barrett's esophagus was also associated with an increased risk of esophageal adenocarcinoma.

Vaughan and colleagues also found that the role of inherited susceptibility to this cancer appears to be much stronger in the early stages of disease - that is, the development of Barrett's esophagus - rather than the progression of Barrett's to cancer.